diff --git a/load_balancer/sites-available/orc b/load_balancer/sites-available/orc
index f8b66ede..38810966 100644
--- a/load_balancer/sites-available/orc
+++ b/load_balancer/sites-available/orc
@@ -86,6 +86,8 @@ server {
     }
     # Prometheus
     location /prometheus/ {
+        auth_basic "Administrator's Area";
+        auth_basic_user_file /etc/letsencrypt/.htpasswd_prometheus;
         # https://github.com/prometheus/prometheus/issues/2193
         proxy_set_header Accept-Encoding "";
         proxy_pass http://prometheus/;